The significantly higher implant failure rates in maxillofacial patients, undergoing radiotherapy, might be caused by the long-term effects of reduced vascularization compromising the implantation site. An extensive preclinical animal literature and a multitude of clinical reports suggest the use of hyperbaric oxygen (HBO) therapy as it can improve the tissue vascularity. Hence, it may increase the implant survival rate by enhancing osseointegration process in such patients. The objective of this systematic review was to investigate the effectiveness of HBO therapy on dental implant survival rate in irradiated maxillofacial patients who require prosthodontic rehabilitation. An electronic search without time restrictions was undertaken in April 2016 using databases: PubMed, Google Scholar, and the Cochrane Oral Health Group Trials Register. We also tried to contact the manufacturers and researchers in the field for necessary details. Clinical human studies, on irradiated maxillofacial dental implant patients, including randomized controlled trials (RCTs), prospective controlled trials, retrospective studies, and preliminary reports were included in the study. Data collection was carried out by two of the authors’ independently. The titles and abstracts of all reports were screened for the study design and type of reported intervention; all the duplicates were removed. The data search yielded 62 titles, out of which 14 articles were selected for the study by the article filtration criteria: Title/abstract/full text. Data which were extracted by two authors with any disagreement were resolved by the third author, and a meta-analysis was done using binary random-effect model. The results show decreased implant failure rate in HBO group (9.21%) compared to non-HBO group (22.44%). The potential limitations of this study are amount of radiation doses used, period lasting from radiotherapy to the placement of the implants, and follow-up period which varies for every subject of the included study, which can affect the treatment outcome. Although there are many sensitive articles published about HBO, including a number of review papers, RCTs are still lacking. According to the statistical analysis, it can be concluded that preventive HBO therapy can reduce the risk of implant failures in irradiated patients by 1.21 (relative risk) with 95% confidence interval (P < 0.001). Hence, HBO can be the effective treatment protocol for the implant treatment in irradiated maxillofacial patients.

Aims:Present study aimed at evaluating the colour stability and flexural strength of flexible denture base materials (Valplast) and Polymethyl methacrylate (PMMA) denture base material (Meliodent) processed by two different methods (Injection moulding and compression moulding) after immersing them in three different denture cleansers with acidic, basic and neutral PH.Methods and Materials:Total 120 specimens (65 × 10 × 3 mm3), 40 specimens of each material (Valplast, Meliodent compression moulding and injection moulding) were immersed in denture cleansers having different PH; Valclean (Acidic), Clinsodent (Basic) and Polident (Neutral) as well as Distilled Water. Color changes were measured with a spectrophotometer after 1 month, 3 months and 6 months of immersion cycle. A flexural 3-point bending test was carried out by using an Instron universal testing machine after 6 months of soaking. Data were analyzed using SPSS softwareResults:Maximum effect on colour stability was noted with Clinsodent followed by Valclean. Least color changes were observed after immersion in Polident. Colour difference was increased significantly as the immersion time increased. For both Meliodent and Nylon resins, statistically significant change in flexural strength occurred with immersion in all denture cleansers. Clinsodent has greater effect as compared to Valclean and Polident.Conclusions:Polident and Valclean can be safely used as denture cleanser for both nylon and acrylic resin denture base materials as far as colour stability and flexural strength both are concerned.

Literatures of this review study have indicated that there are various bio-mechanical reasons, which affect the temperature rise during osteotomy and suggest that the amount of heat generation is a multifactorial in nature and it should be minimized for better primary healing of the implant site.

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The bi-directional DC-DC converter has many applications, such as in hybrid vehicles, solar inverters, in power supplies for microprocessors etc. A bi-directional dc-dc converter can be alternately operated as a step down converter in one direction of energy flow and as step up converter in reverse direction of energy flow, which is from source to load and load to source. A high power supply using a single converter is not preferred as it leads to high ripple in output voltage and current, thus requiring large value of inductor and filter capacitor. To overcome these limitations multiphase interleaving technique is used in bi-directional DC-DC converters i.e. connecting the converters in parallel with the switching instants equally distributed among them. This paper presents the simulation and implementation of two phase bi-directional dc-dc converter.